If you're part of the demographic pursuing joy or just trying to quell some psychic angst, none of this is a surprise to you, nor is the way happiness is now being merchandised, since you may have spent more than your share of disposable income on meditation or yoga classes, life coaching or happiness apps. Part of the solution, however, may lie not in a product or a program but simply in a better understanding of the particular way Americans define happiness in the first place. There are answers to be found in our genes, in our collective psyche, in the workings of our brain. If it was possible for our ancestors to be happy on the prairie, it ought to be possible for us to be happy in our jobs, our families, our communities. We've got all the toys; now we need to relocate the joy, to tap into the propensities that allow us to take pleasure in striving--in, if you will, the pursuit.

The Biology of Happy

The familiar notion that the descendants of immigrants, whether they arrived from old Europe 300 years ago or Asia last year, are heirs to a genetically optimistic temperament makes intuitive sense. But it also makes us uneasy, and it should. That way lies a belief in a sort of breedable, biological specialness--an exceptionalism we accept when it's preceded by the word American but that spooks us when the word is Russian or Chinese or Japanese.

That said, simple biology--evident since Gregor Mendel started breeding his pea plants in the 19th century--dictates that the random mix of genetic traits within any one population will be amplified when that population starts breeding. That ought to be true for so-called immigrant genes too, and in 2011, that idea got a big boost when investigators at Harvard and Boston University analyzed a gene dubbed DRD4, which is associated with activity in the brain's dopamine receptors. The gene comes in several forms, or alleles. Of the three most common, one codes for even-temperedness and reflection, while the other two code for exploratory and impulsive behavior, as well as a taste for risk taking and a tolerance of novelty.

When the investigators looked at the frequency of the different alleles in people around the world, they found that the farther along the migration route from Africa, the cradle of us all, through central Asia, Europe and the New World, the likelier people were to carry the two novelty-seeking alleles. Studies of another gene called 5-HTTLPR, related to serotonin transport, have yielded similar findings. The allele of that gene that codes for anxiety and risk avoidance is less common in individualistic cultures like that of the U.S.

If genes play a role in shaping immigrant temperament, they do so in a subtle way. Serotonin and dopamine are often, simplistically, thought of as feel-good neurotransmitters. The more you have of them, the happier you are. But in the case of immigrants at least, the power of the chemicals is that they regulate what researchers straightforwardly call search activity--forward-looking behavior that often occurs in pursuit of a specific goal. Search activity simply feels good--a fact that helps explain why shopping for something is often more fun than buying it, hunting can be more enjoyable than actually bagging your prey, and so many politicians appear to have a better time running for office than holding it.